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by Dick Cookman
Highlights: Comet Journal, Martian Landers, Meteor Showers, Planet Plotting, January Moon
Focus Constellations: Camelopardalis, Cassiopeia, Cepheus, Draco, Ursa Minor, Ursa Major, Lynx, Gemini, Orion, Taurus, Auriga, Perseus
Comet C/2011 L4 (PanSTARRS) was observed at 8.0 magnitude (Dec. 27, Marco Goiato) and is in Scorpius. It will move into the southern hemisphere skies then will reappear and probably be easily visible to the naked eye when it moves into predawn northern skies in Pisces in March. Comet PanSTARRS may be the first of the Great Comets of 2013. It could be as bright as 1st magnitude when nearest Earth on March 5th and near perihelion on March 10th!
Comet C/2012 S1 (ISON) may have a 33% chance of being a Super Comet! It was observed by D. Pivato at 16th magnitude on December 10th. The 2 mile wide comet was already spewing gases at the time of its discovery on 9/25/12 when it was about 600 million miles from the Sun between the orbits of Jupiter and Saturn. It will circle through northern Gemini until early August, 2013 when it enters Cancer and starts its eastward journey along the ecliptic. The precise orbit of the comet has not been determined but its shape will provide clues as to origin.
If the orbit is parabolic or hyperbolic, this may be its first approach and its probable source was the Oort Belt which is an assemblage of debris, asteroids and minor planets approximately 1 light year from the Sun. First approaches from the Oort Belt are replete with dashed hopes because heating and expansion of abundant gases within the comet often result in fragmentation which may turn potentially spectacular apparitions into duds.
An elliptical orbit would imply that the comet has circuited through the inner Solar System before. Large orbital eccentricity requires a period of many thousands of years, so its last visit may have been as much as 10,000 years ago. Alternatively, the similarity between its orbit and that of the Great Comet of 1680 may indicate that it is a fragment associated with that comet. In either case, previous visits may have resulted in prior ejection of the gases which turn the newcomers into duds and comets as large as C/2012 S1 (ISON) can live up to high expectations.
The comet will pass the orbit of Jupiter in January. By late summer, if it survives the 66% chance that it falls victim to fragmentation, orbit alteration or other comet calamities, it may be visible in a 4 inch diameter telescope. After passing above the orbit of Mars in late September it may be seen with binoculars. Naked eye visibility is predicted to arrive in November when it flies over Earth's January orbital location. By late November, 2013 the comet could even exceed Venus in brightness in predawn skies near Libra when it is near perihelion less than 1.3 million miles from the Sun. After circling the Sun, the comet will start its outward journey and pass less than 0.5 a.u. above Earth's north pole when closest to Earth on Dec. 26th.
Comet 2011 F1 (Linear) will reach perihelion on January 8th, 2013. It is at 9th magnitude and rises in the east in Sagittarius at dawn. It will not be visible for northern observers after January as it drops farther into southern skies.Comet C/2012 K5 ( LINEAR ) is approaching 9th magnitude as it passes through Lynx and into Auriga in early January. It will rapidly move southward and will be in Eridanus by month's end. It reached perihelion above the Sun in late November. The comet drops through the solar system plane only 0.29 A.U. beyond Earth on New Years Day when it could reach 8th magnitude and will then diminish in brightness and disappear from northern skies in the Spring.
NASA's Mars Curiosity rover has used its full array of instruments to analyze Martian soil for the first time and found complex chemistry. Sample analysis revealed water, chlorine, and sulfur containing substances but no evidence of organics.
The rover climbed out of the small depression within Gale Crater in which it landed in August (Bradbury Landing). Then, by early October, it traveled eastward crossing a rise a few hundred meters wide to a sample location on the edge of the rise called Rocknest. It has since conducted a battery of tests on the samples collected. Curiosity then descended to the base of the rise and turned southward into an area called Glenelg where it found a sequence of layered rock formations which displayed some cross-bedding and resembled thin bedded silty shale layers found on Earth. The rover then moved northeastward and descended into a depression called Yellow Knife Bay and proceeded to explore its desiccated surface. By December 17th, Curiosity had logged 677 meters of travel since landing.
From October 23rd (Sol 3110) through November 28th (Sol 3145), Opportunity traveled about 240 meters while completing its circumnavigation of Matijevic Hill on the western margin of Endeavor Crater at the south end of Cape York, the elongated ridge stretching one half mile north-northeastward from Botany Bay. The rover spent the late November and the first week of December completing an extensive color panorama and examining a surface exposure called Sandcherry then it moved to a nearby rock outcrop called Copper Cliff to continue analysis. Solar array energy production has climbed back to 533 watt-hours per day after the dust storm to the south dissipated.
The major meteor shower of January is the Quadrantid shower which peaks on the 3rd. The 3rd quarter Moon will be high in the south in Leo in the predawn hours when North America is close to the leading edge of the Earth as it plows into the remnants of a comet which broke apart about 500 years ago. These remnants include the river of comet debris and a small asteroid (2003 EH1).
The Quadrantids are a major but seldom viewed shower approaching a rate of 60 to 100 meteors per hour in dark skies. The meteors appear to emanate from a northern part of the sky in Bootes and are best viewed from northern latitudes. The clouds which often cover northern skies at this time of year provide a major obstacle for viewing the shower.
January evening planets include Mars, Neptune, Uranus, and Jupiter. Mars (+1.2) moves from Capricornus to Aquarius during the month and sets two hours after the Sun on the 1st. By the 31st the Sun sets 1.5 hours before Mars. the planet is at perihelion on the opposite side of the Sun on the 24th and will remain relatively dim until it starts to brighten at the end of 2013. Neptune (+8.0) in Aquarius sets 4 hours after sunset on the 1st and and less than 2 hours after the Sun at the end of January. Uranus (+5.9) in Pisces sets before midnight and like Neptune is best viewed in binoculars or telescopes. Jupiter in Taurus was at opposition in December and dims from -2.7 to -2.5 magnitude in January. It is a beacon relatively high in the east-southeast after sunset and sets well before dawn. Jupiter will diminish in brightness until it passes conjunction with the Sun in June. Mercury is deep in the glow of dawn in early January. It passes through solar conjunction on the 18th and will appear in sunset skies in Capricornus at the end of the month.
Saturn and Venus are morning planets. Saturn (+0.6 in Libra) rises about 3AM in in early January. It will be high enough in the southeast for good viewing about an hour before dawn. Brilliant Venus (-3.9) moves from Ophiuchus and into Sagittarius in January and drops into the glow of sunrise in the process.
|Mercury||Sagittarius, Capricornus||-0.6 to -1.4 to -1.2||Superior Conjunction, 1/18, 4AM EST|
|Mars||Capricornus, Aquarius||+1.2||Perihelion, 1/24, 4AM|
|Jupiter||Taurus||-2.7 to -2.5|
Lunation 1113 started at New Moon on Dec. 13th. It ends with New Moon at 2:44 PM EST on Jan. 11th and is 28.96 days long. The Full Moon on the 26th at 11:38PM EST is referred to as the "Moon after Yule" or the "Old Moon." Colonial Americans called it the "Winter Moon" and to the Celts it was the "Quite Moon." Chinese call it the "Holiday" Moon. Medieval English named it the "Wolf Moon" and northern Michigan Anishnaabe (Chippewa and Ojibwe) call it "Gichi-manidoo-giizis" (Great Spirit Moon).
The Moon is at perigee on the 10th at 5:57AM EST when it will be at 223,723 miles or 56.45 Earth radii. This is slightly less than 21 hours before the high "Spring Tide" associated with New Moon.
At apogee when the Moon is farthest from Earth on the 22nd at 5:52AM EST, it will be at 63.55 Earth Radii or 251,848 miles from Earth. The Full Moon occurs 4.7 days later making its Spring Tide smaller than normal.
|Planet||Constellation||Magnitude||Moon Passage||Moon Phase/Age|
|Sun||Capricornus||-26.8||3:42AM EST, 12/13||New ~ 0 days|
|Mercury||Sagittarius||-1.0||5.8°N, 7AM EST, 1/11||Waxing Crescent ~ 0.18 days|
|Venus||Sagittarius||-3.9||3.0°N, 7AM EST, 1/10||Waning Crescent ~ 27.66 days|
|Mars||Capricornus||+1.2||6.0°N, 7AM EST, 1/13||Waxing Crescent ~ 2.18 days|
|Jupiter||Taurus||-2.6||0.5°S, 11PM EST, 1/21||Waxing Gibbous ~ 10.84 days|
|Saturn||Libra||+0.6||4.0°S, 8PM EST, 1/6||Waning Crescent ~ 24.68 days|
|Uranus||Pisces||+5.9||5.0°N, Midnight EST, 1/16||Waxing Crescent ~ 4.89 days|
|Neptune||Aquarius||+8.0||6.0°N, Noon EST, 1/14||Waxing Crescent ~ 3.39 days|